Field of the Invention
The present invention relates to an electrode structure of a thin-film transistor.
Descriptions of the Related Art
In recent years, developments for flat panel displays have grown rapidly and traditional cathode radiation tube displays have been gradually replaced. Nowadays, major flat panel displays include: Organic Light-Emitting Diodes Displays (OLEDs), Plasma Display Panel (PDP), Liquid Crystal Displays (LCDs), and Field Emission Displays (FEDs). One of the key components of these flat panel displays includes a thin-film transistor (TFT) so as to control the turn on/off each pixel within these flat panel displays.
As shown in FIG. 1, generally, an electrode structure of a thin-film transistor 1 comprises a gate electrode 10, a source electrode 11, a drain electrode 12, and a semiconductor layer 13. The semiconductor layer 13 is formed above the gate electrode 10 while the source electrode 11 and the drain electrode 12 are formed above a portion of the semiconductor layer 13 and are separated to each other, individually overlapping to a portion of the gate electrode 10. Generally, a width LS of the source electrode and a width LD of the drain electrode are about 4 um. Using this size of the electrode structure in a thin-film transistor so as to control the turn on/off of the pixels is achieved.
However, while current flows through the drain electrode 12 to the source electrode 11, a current flowing from an arc portion 15 of the drain electrode 12 can flow into a circular portion 14 of the source electrode 11 only. Compared to the arc portion 15 of the drain electrode 12, the circular portion 14 of the source electrode 11 has a relatively restricted overlapping area. The circular portion 14 is easily influenced by semiconductor process varieties which further resist normal current flow. This seriously affects the current amount and results in unstable current.
Consequently, increasing and stabilizing the amount of current that flows through the drain electrode 12 to the source electrode 11 without negatively affecting the TFT electrical transmission within displays a necessary objective to endeavor and improve upon.